1. (Field of the Invention)
The present invention relates to an aerosol spay gun used for spraying paint on an object.
2. (Prior Art)
In general, an aerosol spray gun transforms liquid paint into mist or aerosol to jet the aerosol paint stream ahead and directs patterning air to the aerosol paint stream to shape it as desired.
Official Gazette of Japanese Patent Laid-Open No. H2-102755 discloses a hand-held aerosol spay gun capable of altering mass of the spraying pattern. Such an aerosol spray gun has an air flow rate regulating valves in air flow paths through which pressurized air is supplied toward a spraying air outlet and a pattering air outlet close to a nozzle of the gun, and the air flow rate regulating valves cooperative with a trigger serves to supply the spraying air outlet and patterning air outlet with air by an amount corresponding to an amount of squeezing of the trigger, or namely, an amount of ejected paint.
More specifically, the air flow rate regulating valves in the air flow paths within the gun are provided with tapered movable valve shafts coupled to the trigger via links and sprung in a direction equivalent to that of closing the valve, and as the movable valve shafts are correlated with the squeezing of the trigger to come apart from valve seats, an amount of air passing through the air flow rate regulating valves increases linearly.
Allowing for the practice that this type of spray guns are typically used by fully squeezing the trigger, a spray gun described in Official Gazette of Japanese Patent Laid-Open No. H2-102755 has a plurality of circumferential grooves in a shaft of a needle valve that determines an amount of ejected paint, and engagement pieces or stoppers are provided being urged toward the circumferential grooves by means of spring force.
Official Gazette of Japanese Patent Laid-Open No. H2-102755 teaches an improvement in which an air flow rate regulating valve has a movable valve shaft to which linkage is relatively altered in its position to regulate relatively between amounts of ejected paint and air, and in such an improved embodiment, an operator can perform such regulation immediately any time during painting operation because of an engagement element screwed down in the movable valve element so as to attach the movable valve shaft to the linkage. Specifically in this arrangement, a rear end of the movable valve shaft is threaded, and the threaded rear end is screwed down in the engagement element (nut) for attachment of the linkage, so that the operator can manipulate the engagement element to regulate an opening degree in the air flow rate regulating valve any time during the painting operation.
As discussed in the Official Gazette of Japanese Patent Laid-Open No. H2-102755, this type of aerosol spray guns do not stop throttling in relation with the trigger in use but do need fully squeeze the trigger in practice. Allowing for this fact, the aerosol spray gun disclosed in the Official Gazette of Japanese Patent Laid-Open No. H2-102755 can be simplified in configuration in various ways.
The inventor of the present application has devised a new invention in the above-mentioned point of view.
Accordingly, it is an object of the present invention to provide a spray gun selectively used in two modes, between small pattern and large pattern, which can be comprised of simple components.
It is another object of the present invention to provide an aerosol spray gun which can be comprised of a reduced number of components compared with the prior art embodiments.
The present invention provides an aerosol gun, which overcomes technical disadvantages in the prior art as mentioned above and which employs a trigger manipulated by fingers of an operator to regulate an amount of sprayed paint, and the aerosol gun includes:
a throttle valve mechanism that has a movable valve element provided in an internal air duct through which pressurized air is supplied to an outlet of patterning air for shaping aerosol paint stream jetted from the aerosol spray gun;
air hole formed at the tip of the movable valve element for supplying a small amount of air from the internal air duct to the outlet of the patterning air while the movable valve seats on a valve seat; and
a coupling means for coupling the movable valve element to the trigger;
the coupling means comprising a disconnecting means for disconnecting cooperative relation of the trigger with the movable valve element from an initial operation step by an operator of starting squeezing the trigger till a step prior to the one where the trigger is fully squeezed.
Thus, in accordance with the present invention, since the cooperative relation between the trigger and the movable valve element is disconnected by the disconnecting means during the steps prior to the one where the trigger is fully squeezed, the movable valve element continually seats on the valve seat while a small amount of air is supplied through the air hole in the movable valve element to the outlet of the patterning air. Thus, during these steps, paint jetted out is small in both amount and pattern, and this results in the paint being sprayed in a small pattern. When the trigger is fully squeezed, however, such movement of the trigger is transmitted to the movable valve element via the coupling means, and the movable valve element is moved away from the valve seat to remain the throttle valve mechanism open, resulting in a large volume of air being supplied to the outlet of the patterning air. Thus, while the trigger is fully squeezed, the paint jetted out is large in both volume and pattern, and this results in the paint being sprayed in a large pattern.
The operator physically feels repelling spring force that is applied to the movable valve element in the course of gradually squeezing the trigger deeper when the spray pattern turns from the small pattern to a larger pattern. Thus, the operator can spray the paint in the small pattern by squeezing the trigger to such an extent of being about to feeling the spring force, and also can switch the paint spray pattern to the large pattern by fully squeezing the trigger of the spray gun.
Other objects and advantages of the present invention will become apparent from preferred embodiments thereof detailed in the following description.